When the temperatures are in a bottomless drop, a wild bunch of
30 astronomers from all over the world gathers at an abandoned
observatory on the outskirts of Ulaanbaatar, and incredible
fireballs lighten up the skies, if one night "too early", its ...

Chasing the Meteor Storm in Mongolia

With the international expeditions at Khurel Togoot
observatory

A shorter, early report from the expeditions can be found
here! It had been posted to various
astronomy mailing lists on Nov. 20 while the author was still in
Ulaanbaatar. Most of the text and/or information has been
incorporated into this story.

Click on the thumbnails to access 40+ pictures!
(For slow connections the old version w/o
any graphics is still available.)

Getting used to Mongolia

"Mongolia and North Korea have until recently been about as
isolated as the South Pole .... Even today, Mongolia seems like the
end of the earth - outside the few major cities, you begin to wonder
if you haven't stepped into another century rather than another
country." (Lonely Planet shoestring guide North-East
Asia, 1995 edition)

That was to be the place for the astronomical event of the
century? Whole window panes were missing. The single light bulb
on the ceiling was dangling freely, all shades long gone. Instead of
a light switch there were two pieces of metal carrying the full 220
Volts which you had to bring into contact with your bare hands.
And there was no liquid water whatsoever. So this was the famous
"Hotel Edelweiss", the guest quarters of Mongolia's only
professional astronomical observatory "Khurel Togoot", some 11
km Southeast of the capital Ulaanbaatar. It must have been a
state-of-the-art site once - back in the late 1950's and early
1960's, that is, when the socialist "brother nations" from the
Comecon had donated the buildings and half a dozen telescopes to
their poor Far-Eastern partner. There are a coronagraph, a Coude
refractor, a Schmidt camera, meridian instruments and more -
but all equipment is sitting idle now: The state cannot afford to
maintain the place anymore. And the only science that's normally
taking place here is geodesy, thanks to German equipment
monitoring the orbit of the ERS-2 satellite.

Meteor observing,
IMO-style

My best (few)
meteors

Meteor observing:
the pro's

(Links for readers who can't wait for the action - these
links return in the proper places below :-)

It had been evident from the first minute we had arrived here on
Nov. 15, 1998, that this was a strange place. We, that was
"ALEX'98", 14
amateur astronomers from all over Germany, led by Jürgen
Rendtel, president of the International Meteor Organization (IMO), among us many
veteran visual, photographic and video meteor observers. We were
to join a similarly big professional Canadian expedition here,
which in turn had teamed up with the United States Air Force.
Upon our arrival at the place we were immediately shown the
way to the bar and the disco - but no one ever bothered to show us
even one of the astronomical instruments. (That they still exist I
only learned later from a Russian-versed Canadian who had
obtained brief access to some of the domes.) It was clear now that
these "astronomers" would rather go for a drink or likely several
more when night falls rather than ever observe. And the Edelweiss
"hotel" had apparently been home recently not to visiting
astronomers either but to youth groups from the city - this
demonstrated by some ill-fated attempts to spray "Backstreet
Boys" in latin letters onto the walls (Mongolia uses a modified
Cyrillian alphabet).

Operation Meteor Storm...

"'Space Dominance' commander to lead UWO meteor
probe" (Headline of the Canadian London Free Press of
Oct. 8, 1998, reporting on the Canadian expedition. UWO stands
for the University of Western Ontario, but the
American military title isn't exactly accurate. This article was a
continuing source of fun among the astronomers, though ...)

Still, this unlikely place had distinct advantages over
having no roof over your head at all or staying at a ger, the
traditional Mongolian nomad tent. First of all there was
electricity, a rare commodity outside of Ulanbaatar aka. UB, and it
was even stable now (after the Canadians had blown several fuses
during the past week that had mysteriously repaired themselves).
This was good news for the batteries of image intensifier video
cameras and VCR's our group had brought. And there was - at
least during the nights - some heating available in the rooms. This
was particularly good news now since we had heard about a major
mass of cold air arriving shortly from Siberia. During the past 7
days it had been surprisingly mild in the Mongolian countryside,
sometimes even above freezing at night - leading some to complain
that "Mongolian winters are too warm". No one would say that
now: We were to expect clear nights but temperatures of -20 to -25
degrees Celsius, a meteorologist from the U.S. Air Force informed
us, whose forecasts - based on public and military weather
pictures - were always amazingly precise.

Maj. Mike Bedard was responsible for good weather for the
Canadian-American expedition that we now had joined loosely: If
he couldn't guarantee clear skies, there would have been a plan B
in principle, transporting everybody by helicopter into a clear spot
- in the middle of nowhere in the Mongolian steppe, that is. While
this option sounded nice, it probably wouldn't have worked, U.S.
team members readily admit: It had been difficult enough to get
the hi-tech equipment working in the warm Edelweiss rooms.
What were the Canadian astronomers and U.S. military people
doing here anyway? The exact beginnings of this joint meteor
hunt - that has cost the Canadian and the U.S. tax payers about 1
million Canadian dollars (who paid how much is not clear) - go
back to a scientific conference in Canada. It had been organized by
Peter Brown, a graduate student at UWO and already a widely
respected authority on meteor streams. And among the
participants was Col. Pete Worden of the U.S.A.F., originally a solar
astronomer who had also been involved in the BMDO's
Clementine lunar orbiter mission and had made himself a name
in science circles as well. Both scientists eventually agreed to join
forces in getting the most accurate record of the upcoming Leonid
meteor activity.

For Brown it was basic science. He had already published
countless scientific papers on meteor streams and was highly
regarded in this field. Like many he had tried his luck in
predicting the 1998 activity level of the Leonids. Using historical
observations, orbital models and the observed activity of the past
few years his final statement (of Nov. 5th) was: There will be 1200
+/- 280 meteors per hour for a single visual observer under
optimum conditions (the so-called Zenithal Hourly Rate or ZHR)
during peak time, i.e. the evening of Nov. 17 UTC, and possibly
more. This prediction fell well into the range of other estimates
(that had been anywhere between 200 and 15 000 per hour).
Brown's intention was to record the time profile of the Leonid
activity as accurately as possible, using not only the established
method of visual counting but especially video methods. Modern
video cameras, combined with image intensifier tubes (i.e. night
vision equipment) give you a live image of the sky (at video rate, i.e.
30 frames per second for NTSC) with a limiting magnitude around
8m. So you could record everything on tape for later detailled
analysis - without the danger of being overwhelmed by very high
rates that were still thought to be a distinct possibility.

Col. Worden's intentions were more of the practical kind. Since
about a year before the predicted Leonid peak there had been
worries among satellite operators all over the world. While there is
still no hard evidence that even one satellite has ever been knocked
out by a meteoroid, a probability of several in a thousand was
calculated that any given working satellite in orbit could be
damaged by a Leonid particle - if there would be high activity. With
their high speed - 71 km/s - the Leonids were even more
dangerous than ordinary interplanetary dust particles. Different
approaches were taken by commercial and government operators,
with some basically ignoring the possible threat and others
turning their satellites into the least vulnerable positions. But the
Air Force wanted to go one step further: It asked for near real-time
analysis of the Leonids activity level, to aid its operations in
making decisions. The Khurel Togoot team was one of three that
had been dispatched by the Canadians and Americans: another
visual/video group was located some 50 km to the South of Khurel
Togoot (staying in gers) while a radar/visual team had gone to the
Tindal AFB in Northern Australia and a Bombing Range 170 km
away. All were to report the meteor rate every 15 minutes to a data
center set up at Western University in Canada. It was an
operation never tried before - let alone from one of the most
isolated and lonely places of Earth.

Surveying the countryside: into the
unknown

"The world pays more attention when one person dies in
America than when 10 die in Mongolia. But we have a proud
history of stamping half the world with our horses' hooves, and
history tends to come full circle." (Conclusion of an article in
the UB Post of
Oct. 27, 1998, that dealt with a current
trend in Mongolia
to copy everything American)

While the Canadians and Americans had installed and debugged
their video, computer and communications equipment at the
observatory, the German group had spend its first week travelling
around Mongolia.
Or rather, trying to gather
some impressions of
the two Mongolias. There is probably no other country in
the world with such a sharp contrast between the one major city,
Ulaanbaatar or "UB", and the remainder of the land - all 1.6 million
square kilometers of it. Of the about 2.4 million inhabitants, some
700 000 live in UB while the rest is all but vanishing in the vast
open spaces. With 1.5 people living on one square kilometer on
average, Mongolia has one of the lowest population densities in
the world (the respective value for Germany is 228/sqm!). On the
other hand, Mongolia
also has a livestock population of 31 million,
including 14 million sheep: Long before you encounter a human in
the Momgolian steppe, you're likely to find some sheep, goats,
cattle, horses or yaks - or the ominous traces they've left behind
in the short grass of the late fall... The landscape in this part of
central Mongolia is largely rolling terrain without any trees,
somewhat depressing in November maybe - but tons of it, and
after the next hill more of the same. And having no streets and no
cities also means having no lights: The night skies over our gers
were wonderfully dark, leading some to start their meteor counts
(some Taurids and sporadics).

Into the central Mongolian steppe!

To get around easily we had rented four Russian jeeps, including
drivers, that brought us to the ger village of Chugun Chaan 280
km West of UB - set up only for tourists, all right, but otherwise
pretty authentic. The gers were exactly the same ones used by the
nomads around the country, with a powerful stove in the center -
but no running water anywhere and 'toilet' facilities defying
description (a good preparation for the encounter with the
related, err, 'installations' at the observatory, though). The food
was fine, however, one night the drivers even gave an excellent folk
concert for us - and ever having gotten to the remote place
between imposing rocks and next to a fancy sand dune had
already been half the fun. At first the road leading out of UB had
been surprisingly good, but eventually it dissolved into something
more adventurous - and some of the drivers obviously felt much
better driving off-road through the steppe than dodging potholes.
A daytrip from Chugun Chaan to Charchorin - the old
Karakorum
of Chinggis Khaan's time, now mainly famous for a
large monastery - had then exposed us to the full spectrum of
Mongolian 'road' conditions, with jeeps getting stuck in rivers for
a change.

A visit with the nomads

Karakorum

Later one of the drivers sped past a police check point what lead to
a interesting chase (two policeman on a small motorbike vs. his
jeep) up a steep hill overlooking Charchorin - while the driver got
his license confiscated (a fact that didn't stop him continue
driving) we enjoyed an extremely bright sun dog halo
phenomenon. There was also the obligatory confrontation with
the original nomad culture (when one ignores the nowadays
almost ubiquitous solar arrays on the ger roofs): We were led to a
nomad family that the travel agency is doing horse business with.
While the language barriers prevented any useful communication,
we did get to get to taste the (in-)famous
airag (fermented
mare's milk), mutton cooked with hot stones (and even more
bones) in a big milk can, and other food items we still haven't
identified. Maybe that's for the better... Decidedly more fun for
some in the group were the close encounters with some of the
family's cattle that one of us actually got to milk - vacation on a farm,
Mongolian style. At this point the weather had started to turn
nasty, with a snow front approaching - for the first time during
the journey there would be no blues skies and brilliant sunset. But
it was time to return to UB anyway, to treat those who had
already fallen sick - quite a number - and to prepare for the 4-day
stay at the observatory (known to us just as "the obs").

The night of the fireballs

"Veteran meteor observers among both the German team and
our team say that this is the most impressive fireball display
they've ever seen." (Col. S.P. Worden during an impromptu
news conference at the obs on the morning of Nov. 18 - when he
had to explain to the assembled media that the big show had
already happened the night before)

Sometimes it pays when "the Pentagon is sending its best
meteorologist" (London Free Press) to be on your
astronomical field trip. It was snowing heavily in UB - where one
week earlier I had seen a brilliant green flash of the setting Sun
from our hotel roof - when we boarded our buses for the obs. But
Maj. Mike Bedard had assured me that the system would pass
and that the next four nights would be o.k. - no need for the
choppers. But he had also predicted very cold air following the
snow front, and indeed the temperature forecast map of
CNN's Asian service had painted Siberia and our part of
the world in deep blue and purple tones I had never seen before.
And they were also predicting one of the harshest winters in
Russia in 30 years! Now we would get an early taste of it, but then
again some in the group had spent over 1000 DEM for special
arctic-proof clothing. In this respect the mood was upbeat. And
the first night of observations - Nov. 15 to 16 Mongolian Time =
the evening of Nov. 15 UTC - lived up to expectations in that
hardly any meteors were sighted. This was what everyone had
predicted, and actually most also believed that there wouldn't be
many meteors the next night. That would be exactly 24 hours
before nodal crossing, and the general expectations were that any
background activity from older Leonid particles would only start
to ramp up 12 hours before the crossing. How wrong the experts
could be sometimes...

Usually we would go to bed around 8 p.m. to get up again around 2
a.m. when Leo and the radiant would already have risen (the
Lion's had came above the horizon almost exactly at midnight
local time, which is 8 hours ahead of UTC). But tonight there was
no need for an alarm clock: Those observers who had gotten up
early made sure no one overslept tonight. Something totally
unexpected was going on: We were literally under fire from a hail of
large meteoroid particles. There was at least one meteor visible
every minute - normally no big deal, but all of them were very
bright. Not one was faint. This was a most unusual brightness
distribution: Normally you have many more fainter than bright
ones, and we would have seen the faint ones easily (the limiting
magnitude was always better than +6m). But now they were all
brilliant - and some strikingly so. One, for example, had about the
brightness of the full moon and exploded right in the zenith: Its
train (the ionized trail of atmosphere where the particle burnt up)
kept on glowing for many minutes, and you could see it being
distorted by the winds in the upper atmosphere. At times there
would be several meteor trains visible in the sky at the
same time - something exceedingly rare, as you normally have
only a few significant trains during a whole night. Who cared that
it was -30 degress Celsius or below?

With Leo and the radiant climbing higher and higher, the number
of meteors per hour climbed, too. This was not simply due to the improving
geometrical conditions: The meteor rate was really rising fast, as the
IMO Analysis
would later show - the peak rate wouldn't be reached until 1:30 UTC =
7:30 Mongolian time. But we were in a good spot nonetheless: A single
observer in Mongolia could easily see 100 Leonids, all rather to very
bright, in one hour around 6 a.m. on Nov. 17th (22:00 UTC on Nov. 16th).The
ZHR at the time was around 200, according to the global analysis.
As usual, there would be lulls in activity and then rapid fire
from the sky, like 5 meteors within less than half a minute. Now
imagine 5 meteors within a second - some optimistic models had
thought that possible 24 hours from now. But would it happen
after all? The models had been dead wrong about the ramping up
of the background particle component we had seen so
spectacularly tonight (and that the Europeans were just now
starting to experience - if they had clear skies and had
bothered to observe one night "early"). There was a distinct
possibility now that the whole prediction business was off and
that the "real" maximum the next night could be a dud. There was
only one way to find out...

The colonel calls off the storm...

"'This is a very inexact science,' noted German astronomer
Daniel Fischer, according to AFP. 'Some say because the historical
evidence is so poor, nobody should make any predictions,
period.'" (From the article "METEOR MADNESS" in the Tabloid News Services of
Nov. 18, making reference to a comment I
actually made during an interview for a Canadian radio station -
some hours before the maximum was expected)

During the expected "maximum" night the Khurel Togoot
observatory - normally a largely deserted place - was not only
host to about 30 astronomers from all over the world but also a
surprisingly large number of journalists apparently called there
by the Americans and Canadians. Most were international
correspondents based in UB, but one had actually flown in from
Canada just for the night. By pure coincidence a handfull of bright
meteors kept the spirits of the freezing crowd high just when
Leo's head rose around midnight Mongolian time (which is 16:00
UTC on Nov. 17). But it soon became clear that there would be no
replay of the stunning fireball show from 20 hours ago (that had
peaked with a ZHR of roughly 340 meteors per hour near 1:30 UTC or 9:30
Mongolian time this morning, according to the IMO paper).
Mainly faint meteors could be spotted now, all right (with a ZHR somewhat
around 100), but there was no serious increase of the rate when
the 'magical' time of nodal crossing (ca. 3:30 local time) came
closer. At 2:20 Mongolian time (18:20 UTC) Col. Worden broke the
bad news to the press: "We're not seeing any increase that would
indicate we'll have a major storm in the next few hours," he stated
and suggested that one might as well go home. "Do you have any
idea what happened?" someone inquired - Worden: "No!" But let
there be no mistake: Last night's "very very strong bright shower
of fireballs," according to Worden, "was probably one of the more
impressive fireball shows on record." For him personally "that's
the most impressive thing I've ever seen in the sky."

The authors's Leonid pictures
(same link as above)

Amazingly the fireball storm - if one chooses to call that rare
phenomenon that - had been a global phenomenon: It had
"persisted obviously for at least 18 hours, because we have reports
from across Europe and N. America, some of them visible in
daylight - this is a very unusual situation," Worden summarized
the first news that had reached him. A preponderance of fireballs
long before nodal crossing is not exactly new, however, as Worden
reminded the reporters: "1965 had a broad peak of very very
bright meteors that lasted for 36 hours" - and was followed by a
no-show at nodal crossing. 1966, however, had then brought a
tremendous meteor storm at crossing time. For 1998 nearly all
models had anticipated a profile similar to 1966, with a
pronounced - although much smaller - peak at nodal crossing.
Why the forecasts failed so completely is now a major mystery. It
only seems clear that the big particles that the Earth had
encountered well before - but not during - nodal crossing had been
released by comet Tempel-Tuttle several hundred years ago. Since
there were so many, Tempel-Tuttle must have experienced "a
pretty major set of events" (Worden) back then. The small
particles the Earth was encountering right now in contrast were
young.

It's science, after all...

"But scientists admit their knowledge of meteor streams is
imperfect - and there's a small chance the shower won't live up to
expectations. 'It's like weather forecasting,' says Worden.
'Sometimes they're right, and sometimes they're wrong." (J.
Lawless, writing in the UB
Post of Nov. 17, 1998 - one of
the better pre-shower articles in the Mongolian press. Here is her
Nov. 24 article.The
Mongol Messenger, in contrast, knew in its Nov. 11 edition
that "this meteor shower was first documented by Alexander
Humbold Leonid" and boldly claimed in its Nov. 18 edition that "40
meteors per second" were seen last night - maybe they should
write their stories after the event the next time ...)

With this night's fresh insights into the vagaries of meteoritical
science swallowed with the help of a few free beers (courtesy of the
U.S. embassy) most of the press had left by 3:30 a.m., leaving
behind the astronomers on the observatory who had largely
missed Worden's 'official' cancellation of the show an hour earlier.
There were the other members of our German IMO expedition who
had mostly gathered on an isolated rock and were recording the
meteor activity with an array of video cameras with image
intensifiers, photographic cameras and visually. The
video
equipment had been deemed particularly important because it
would have yielded the first-ever objective record of a meteor
storm - if there had been one. The has been much debate about the
actual number of meteors in the sky during the famous 1966
Leonids storm: Video would nail the number down reliably and
even help re-calibrate the old visual counts (and finally prove that
there were really 40 meteors per second visible then). Last night
individual visual observers had seen up to 100 meteors in one
hour, most of them very bright or fireballs, often leaving
spectacular trains behind.

IMO at work
(same link as above)

Now still some 35 to 40 meteors could be spotted in an hour, but
the fireballs were largely gone, and the ZHR was clearly down. And
by the next night (18/19 Nov.) the observed meteor rate would
have dropped off dramatically, to some 10 Leonids per hour. The
observing logs, photographs (hopefully) and especially the
roughly 100 hours of videotape from all 4 nights will be a major
source for further studies, perhaps helping in the end to explain
"what went wrong" or rather why everything went so differently
from the expectations this year. Rather similar data material has
been collected by the
Canadian-U.S. expedition:
Here, too, a battery
of video cameras had been pointed at the sky, even from two sites
(to get redundancy, plus 3D vectors for selected meteors), and
visual counts had been made as well. But the highly organized
effort had had that second objective well beyond basic research, of
course: The visual counts as well as the data gleaned in real-time
from one of the video cameras (by an experimental computer
program, 'Meteorscan', as well as from someone constantly
watching a monitor) were telephoned every 15 minutes to Canada.

The pro's at work
(same link as above)

A typical message going out via satellite telephone would sound
like this (an actual example from the morning of Nov. 18):
"Mongolia Observatory. We have counts of 11 for automated
detection, 4 for TV and the human observer, limiting magnitude
was 8.0, the visual observer outside was 22, and the limiting
magnitude now is 6.0 - over." Canada would read back the
numbers, and that would be it for the next 15 minutes - satellite
time is expensive. From the Canadian center the information -
now transformed to ZHR's - would eventually be passed on to the
55th Space
Weather Squadron at Schriever AFB in Colorado
Springs, Colorado, U.S.A., which would have warned satellite
operators in case of a real storm brewing. None had been, of
course, and no obvious satellite anomalies were reported either:
The Mongolian experiment had mainly become a demonstration
of principle. But interestingly the prolonged exposure to
comparatively large meteoroids for 24 hours could in principle be
as harmful to satellites as a strong but short peak of activity. The
further analysis of the Mongolian tapes and data in the coming
months will help to quantify this possibility - and will hopefully
lead to better predictions for the 1999 Leonids (that no one dares
to make right now).

The generally positive experience with the real-time analysis of
meteor videos could one day lead to a world-wide network of
automated monitoring stations - perhaps associated with an
already existing network of U.S.A.F. telescopes keeping an eye on
the Sun. The 1998 Leonids didn't live up to some peoples'
expectations, no doubt, but they will eventually bring forward
meteor science a great deal. And on an 'operational' level they have
already made history. As Aviation Week & Space
Technology further reports, the whole ZHR-in-real-time
business with the two Mongolian sites and the Australian one was
deemed a success: "Field teams in northwestern Australia and
Mongolia sent radar and optical data every 15 min. to a laboratory
at the University of Western Ontario. After processing, ZHR
readings were forwarded to the 55th Weather Sqdn. at Schriever
AFB, which provided the information to squadrons charged with
controlling about 60 military satellites, including the Navstar
constellation" (that provides the Global Positioning System).
Staffing had been increased at the control centers, but nothing
happened. The satellite controllers, at least, had 100% reason to
celebrate.

Impressions of "UB"

November 19th was the day of packing up, and by nightfall most
of the Khurel Togoot observers had returned to the civilization of
UB, with liquid water and even WC's. A quick survey of the - few -
Mongolian-language dailies for sale in the city yielded only one
obvious result: a nice time-exposure of Leo with two meteors,
clearly pointing back to the radiant near the Lion's neck. This
picture, of course, had been taken on the now-famous morning of
Nov. 17. The next day would give me the opportunity to scan the
WWW from the
International School of Ulaanbaatar (ISU) for 8
hours, yielding tons of articles on the Leonids from several
continents. I could also use their computer - after an hour-long
fight with Windows95 to get a job done that Unix accomplishes in
seconds - to send a first report to various
mailing lists. In exchange for so much hospitality I gave a
presentation on our Leonids experience to the school's students:
Many of them had been at the observatory on the night of Nov.
17/18. That was the first public talk on our
expedition - and the
video material premiered later that day as well, during a reception
at the German embassy. Many spectacular Leonids had been
captured by the cameras, including one so bright that the image
intensifier was completely saturated for a second. Even more
spectacular were timelapse movies of bright meteor trains.

At the Circus

People of Mongolia

This party would normally have been almost the conclusion of our
Mongolian experience - but on Saturday rumors consolidated that
there was a problem with the airplane that was supposed to get us
back to Berlin on Nov. 22. It turned out that the Mongolian airline
MIAT had only two Airbus
planes capable of this journey: One was undergoing maintenance
in Japan - and the other was stuck in Frankfurt where two
engines had to be replaced! Incidentally, MIAT's services had broken
down one week before as well, because of ice on
the runway ... Before the plane finally showed up in
UB on the morning of Nov. 24, there was ample time to explore
more of the city, check out some of the newer restaurants (UB is
far more evolved in this respect than the large Siberian cities such
as Irkutsk), markets (full of fresh fruits and merchandise from
around the globe) and the Mongolian State Circus. Also, another
visit to the ISU allowed us to send more e-mails back to Europe.
And when the plane finally took off, the 8-hour-long return to
Germany was almost boringly uneventful. The journey was
suddenly over, but the analysis of the data material has hardly
begun. And then someone has to step forward and make a
prediction where the 1999 Leonids would be seen best. All bets are
off at the moment - and most Europeans have already vowed not
to venture farther than the Southern Mediterranean next
time...

Pictures added and text slightly updated (with new IMO results) on Dec. 11.
Originally written on Nov. 27, 1998. A minor part of this story had
already been typed at the International School of Ulaanbaatar on
Nov. 20, 1998 - thanks a lot for the unique opportunity!